This is quite interesting mechanism, so I decided to describe it in details in the separate thread.
Ok, so first picture shows something that I didn't pay attention to. Please notice 10 vertical metal bars
attached to fuselage, they mark horizontal stabilizer movement area. It moves together with fairings that attached to it.
There is a little space between fuselage and this fairing. Rotation axis is located near the elevator hinges.

trim_marks.jpg (82.95 KiB) Viewed 373 times

So let's remove these fairings and look what's inside (thanks to Caroline):

caroline.jpg (45.33 KiB) Viewed 373 times

All pictures by famous John Oder. His webpage www.aeromuseumservices.com is not available anymore, so I decided to post these pictures here to save this information for others.